Mold closure apparatus



J1me 1967 u. EGGENEBERGER MOLD CLOSURE APPARATUS Filed Nov. 21, 1962 United States Patent O M 3,327,353 MOLD CLOSURE APPARATUS Ulrich Eggenberger, Uzwil, Saint Gall, Switzerland, assignor to Gebruder Buhler, Saint Gall, Switzerland Filed Nov. 21, 1962, Scr. No. 239,258

Claims priority, application Switzerland, Nov. 21, 1961,

13,534/ 61 3 Claims. (CI. 18-30) In pressure casting or die casting machines the mold generally consists of two parts. One of these parts is secured to a fixed mold carrier and the other to a movable mold carrier. The stationary mold carrier is firmly connected to a crosshead which supports the device for positioning the movable mold carrier and for producing the required closure force. A substantial path must be covered by the movable mold carrier, in order to enable the removal of the workpiece from the mold. n the other hand, a considerable closure force is necessary for resisting such a casting pressure.

The apparatus for closing molds according to the present invention comprises a crosshead having movable front and rear members, between which members a chamber is formed into which pressure fluid can be admitted, for producing a closure force, mechanical elements being provided for advancing the movable mold carrier and supporting it against the front member of the crosshead and at least one wedge member being provided for locking purposes between the front member and the rear member of the crosshead. V

The present invention will now be described in more detail with reference to the accompanying drawings illustrating, by way of example, a preferred embodiment of the mold closing device according to the invention, and in which:

FIGURE 1 is a vertical section through the apparatus in the open mold position.

FIGURE 2 shows the apparatus according to FIGURE 1 in the closed mold position, and

FIGURE 3 is a fragmentary horizontal sectional view of the crosshead according to the invention.

Referring more particularly to FIGURE 1 of the drawings, one mold half A is secured to a stationary mold carrier 1 which supports the casting sleeve 2 together with the transfer plunger 3. The stationary mold carrier 1 is connected by four rods 4 of circular cross section to a rear part 5 of a crosshead consisting of two parts 5 and 8 and designated as a whole by the numeral 6; the part 5 is fixed to the stationary frame 7 of the machine. The front part 8 of the crosshead 6 is movable along the machine frame 7 and comprises a plunger 9 of large diameter engaging a cylinder 10 formed in the rear part 5 of the crosshead; a pressure chamber 11 is formed between the plunger 9 and the cylinder and can be supplied by pressure fluid through a conduit 11a, so that the front part 8 and the rear part 5 are forced apart from each other by the action of the fluid against the influence of springs 25 (see also FIGURE 3) which abut against the rear part 5 and act upon the front part 8 by means of pull rods 26. Wedges 12 of which each is actuated by a double acting plunger 13, are provided between front part 8 and rear part 5 of the crosshead 6. The plungers 13 are arranged in the rear part 5 of the crosshead each in a cylinder 14. Pressure fluid can be supplied to both sides of the plungers 13, so that the wedges 12 may hydraulically be moved towards each other or apart from each other. The angle of the wedges 12 is selected so that any axial pressure exerted upon the front part 8 of the crosshead cannot cause these wedges to move.

The front part 8 of the crosshead 6 is provided with a cylinder 15 including a double acting plunger 16. The

Patented June 27, 1967 cylinder can be supplied with pressure fluid on both sides of the plunger 16 through conduits not illustrated. The plunger rod 17 carries on its outer end a plate 18 which is connected to links 20 by means of arms 19. The arms 19 are pivotally connected to the middle zone of the links 20, of which the ends facing the mold 1 are coupled to the movable mold carrier 21. In the position of the mold closure apparatus illustrated in FIGURE 1 the links 20 engage guide surfaces 22 arranged in the front part 8 of the crosshead 6. When displacing the movable mold carrier 21 to the position shown in FIG- URE 2 :by means of the plunger 16, the links 20 first slide along the guide surfaces 22; however, they will be spread apart by the arms 19 which are inclined towards the axis of the machine, as soon as the inner link ends, upon the closure movement of the mold carrier 21, clean the guide surfaces of the front part 8 of the crosshead. In the closed position of the mold according to FIGURE 2, the links are supported in seats or bearings 23 of the front part 8 and in seats on bearings 24 of the movable mold carrier 21.

During the closure movement of the mold, the pressure fluid acting on the plunger 16 must only move the lever mechanism formed by the links 20, the arms 19 and the movable mold carrier 21 together with the mold half B attached to the latter, i.e. a relatively small mass, and must overcome only the friction of the various parts so that the required power is comparatively small and the closure movement can be carried out relatively fast by means of a plunger of comparatively small diameter without requiring the use of an excessive amount of pressure fluid. After the links 20 at the end of the closure movement have been spread apart and are supported in their bearings 23 and 24 without any load, the plunger 9 is subjected to pressure and owing to its relatively large diameter can produce a considerable closure force. Its path however, is short, so that again a small quantity of pressure fluid only is required. Finally, the wedges 12 are pushed inwardly by means of the plungers 13. As the movable mold carrier 21 is supported by mechanical elements, in the present case :by the links 20, against the front part 8 of the crosshead 6, and since between the front part 8 of the crosshead 6 and the rear part thereof at least one wedge 12 is provided for locking purposes, the power connection effected by the closure force is obtained exclusively by means of mechanical elements. In this case the operation is independent of changes caused by temperature conditions, since the wedges 12 will be moved more or less far according to these changes. The force by means of which they are moved can be kept constant. Owing to the mechanical locking arrangement the mold halves remain firmly applied against each other even during the substantial pressure shock resulting from the movement of the transfer plunger 3. After solidification of the casting, the pressure within the pressure chamber 11 is somewhat increased, so that the wedges 12 may easily be disengaged by the plungers 13. When the wedges are disengaged, the pressure chamber 11 is relieved. All mechanical elements are released of tension, and may now be actuated without great expenditure of force.

Retracting of the movable carrier 21 to the open mold position according to FIGURE 1 is again effected by means of the plunger 16 which moves to the left in the drawings under the influence of the pressure fluid acting on the right hand or smaller plunger surface and takes along the plate 18 and the arms 19. The latter move the links 20 towards each other until the link ends are able to enter into the guide paths 22. The mold is then opened and the casting can be pushed out by ejection elements known per se and not known. The empty space behind the movable mold carrier'21 affords great freedom in the structural design and accommodation of such ejection elements. For the same reason the particular mold half may also easily be secured to the movable mold carrier 21.

It is understood that the invention is not limited to the details of the foregoing example. Owing to the relatively small masses to be moved when closing the mold, the cylinder 15 together with the plunger 16 may for example be arranged behind the crosshead and secured to the rear part of the crosshead, without taking the risk of endangering relatively long plunger rod 17, which in this case is traversing the chamber 11, by buckling stress.

I claim:

1. Apparatus for closing molds, comprising movable and stationary mold carriers, a crosshead including relatively movable front and rear parts, a chamber formed between said front and rear parts and adapted to be supplied with pressure fluid for producing the closing force, a pressure fluid actuated mechanical linkage connected between said front part of said crosshead and said movable mold carrier for moving and supporting said movable mold carrier, and movable wedge means between said front and rear parts of the crosshead for locking said parts against relative movement.

2. Apparatus for closing molds comprising movable and stationary mold carriers, a crosshead including relatively movable front and rear parts, a chamber formed between said front and rear parts and adapted to be supplied with pressure fluid for producing the closing force, said front part of the crosshead being provided with guide surfaces extending in the direction of movement of the movable mold carrier, guide links having one of their ends pivotally connected to said movable mold carrier and the other ends being adapted to engage with and slide along said guide surfaces of the front part of said crosshead, said front part being provided with bearings adapted to engage said guide links for supporting the movable mold carrier in closed position, and a pressure fluid operated spreading mechanism coacting with said guide links for pivoting the links into engagement with said bearings upon the movable mold carrier arriving in its position of closure.

3. Apparatus for closing molds, comprising a fixed mold carrier and a movable mold carrier, means for guiding said movable mold carrier toward and away from said fixed mold carrier, a crosshead including relatively movable front and rear parts, said front and rear parts being shaped to form a pressure chamber therebetween adapted 1301136 supplied with pressure fluid for producing a closing force on said movable mold carrier, a pressure fluid actuated linkage connected between movable mold carrier and said front part of said crosshead including a piston movable to displace said movable mold carrier toward said fixed mold carrier and a linkage displaceable upon a predetermined movement of said movable mold carrier to abut between said movable mold carrier and said front part of said crosshead for moving said movable mold carrier with said front part of said crosshead when said front part of said crosshead is displaced away from the rear part of said crosshead by applying pressure in the chamber formed therebetween, and a wedge member movable in the space between said front and rear portions of said crosshead when the latter portions are displaced away from each other, at least one of said rear and front portions of said crosshead defining a surface cooperatively engaging with said wedge member for locking said front and rear parts of said crosshead against relative movement.

References Cited UNITED STATES PATENTS 2,371,547 3/1945 Rosenlund et a1. 18-30 2,618,823 11/1952 Perkon 18-30 X 2,689,978 9/1954 Roger 18--30 -WILLIAM J. STEPHENSON, Primary Examiner.

MICHAEL V. BRINDISI, Examiner.

J. HOWARD FLINT, JR., MARCUS U. LYONS, H. E. MINCH-EW, W. L. MCBAY, Assistant Examiners. 

1. APPARATUS FOR CLOSING MOLDS, COMPRISING MOVABLE AND STATIONARY MOLD CARRIERS, A CROSSHEAD INCLUDING RELATIVELY MOVABLE FRONT AND REAR PARTS, A CHAMBER FORMED BETWEEN SAID FRONT AND REAR PARTS AND ADAPTED TO BE SUPPLIED WITH PRESSURE FLUID FOR PRODUCING THE CLOSING FORCE, A PRESSURE FLUID ACTUATED MECHANICAL LINKAGE CONNECTED BETWEEN SAID FRONT PART OF SAID CROSSHEAD AND SAID MOVABLE MOLD CARRIER FOR MOVING AND SUPPORTING SAID MOVABLE MOLD CARRIER, AND MOVABLE WEDGE MEANS BETWEEN SAID FRONT AND REAR PARTS OF THE CROSSHEAD FOR LOCKING SAID PARTS AGAINST RELATIVE MOVEMENT. 